Flying buttress
Overview
 
A flying buttress is a specific form of buttress
Buttress
A buttress is an architectural structure built against or projecting from a wall which serves to support or reinforce the wall...

ing most strongly associated with Gothic church architecture
Gothic architecture
Gothic architecture is a style of architecture that flourished during the high and late medieval period. It evolved from Romanesque architecture and was succeeded by Renaissance architecture....

. The purpose of any buttress is to resist the lateral forces pushing a wall outwards (which may arise from stone vaulted
Vault (architecture)
A Vault is an architectural term for an arched form used to provide a space with a ceiling or roof. The parts of a vault exert lateral thrust that require a counter resistance. When vaults are built underground, the ground gives all the resistance required...

 ceilings or from wind-loading on roofs) by redirecting them to the ground. The characteristic of a flying buttress is that the buttress is not in contact with the wall all the way to the ground; so that the lateral forces are transmitted across an intervening space.
Encyclopedia
A flying buttress is a specific form of buttress
Buttress
A buttress is an architectural structure built against or projecting from a wall which serves to support or reinforce the wall...

ing most strongly associated with Gothic church architecture
Gothic architecture
Gothic architecture is a style of architecture that flourished during the high and late medieval period. It evolved from Romanesque architecture and was succeeded by Renaissance architecture....

. The purpose of any buttress is to resist the lateral forces pushing a wall outwards (which may arise from stone vaulted
Vault (architecture)
A Vault is an architectural term for an arched form used to provide a space with a ceiling or roof. The parts of a vault exert lateral thrust that require a counter resistance. When vaults are built underground, the ground gives all the resistance required...

 ceilings or from wind-loading on roofs) by redirecting them to the ground. The characteristic of a flying buttress is that the buttress is not in contact with the wall all the way to the ground; so that the lateral forces are transmitted across an intervening space. Flying buttress systems have two key components - a massive vertical masonry block (the buttress) on the outside of the building and a segmental or quadrant arch bridging the gap between that buttress and the wall (the 'flyer').

History

Although fully fledged flying buttresses only developed in the Gothic period
Gothic architecture
Gothic architecture is a style of architecture that flourished during the high and late medieval period. It evolved from Romanesque architecture and was succeeded by Renaissance architecture....

, their precursors can be found in Byzantine architecture
Byzantine architecture
Byzantine architecture is the architecture of the Byzantine Empire. The empire gradually emerged as a distinct artistic and cultural entity from what is today referred to as the Roman Empire after AD 330, when the Roman Emperor Constantine moved the capital of the Roman Empire east from Rome to...

 and in some Romanesque
Romanesque architecture
Romanesque architecture is an architectural style of Medieval Europe characterised by semi-circular arches. There is no consensus for the beginning date of the Romanesque architecture, with proposals ranging from the 6th to the 10th century. It developed in the 12th century into the Gothic style,...

 buildings, such as Durham Cathedral
Durham Cathedral
The Cathedral Church of Christ, Blessed Mary the Virgin and St Cuthbert of Durham is a cathedral in the city of Durham, England, the seat of the Anglican Bishop of Durham. The Bishopric dates from 995, with the present cathedral being founded in AD 1093...

, where quadrant arches were used to carry the lateral thrust of the stone vault over the aisles. However these arches were hidden under the gallery roof and only transmitted the forces to the massive outer walls. By the 1160s, architects in the Île-de-France
Île-de-France (province)
The province of Île-de-France or Isle de France is an historical province of France, and the one at the centre of power during most of French history...

 were employing similar systems but with longer and finer arches running from the outer surface of the clerestory wall, over the roof of the side aisles (and hence visible from the outside) to meet a heavy vertical buttress rising above the level of the outer wall. The main advantage of such systems is that the outer walls no longer need to be heavy and massive enough to resist the lateral thrusts of the vault. Instead the wall surface could be reduced (allowing larger windows filled with stained glass), with the vertical mass concentrated into external buttresses.
Early flying buttresses tended to be far heavier than is required for the static loads involved, as for example at Chartres (c. 1210) and around the apse
Apse
In architecture, the apse is a semicircular recess covered with a hemispherical vault or semi-dome...

 of the Basilica of St Remi in Reims, which is thought to be among the earliest examples still surviving in its original form (dating from around 1170). Later architects progressively refined these designs and slimmed down the flyers until typically they were constructed from no more than one thickness of voussoir
Voussoir
A voussoir is a wedge-shaped element, typically a stone, used in building an arch or vault.Although each unit in an arch or vault is a voussoir, two units are of distinct functional importance: the keystone and the springer. The keystone is the center stone or masonry unit at the apex of an arch. A...

 with a capping stone above it (see for example the cathedrals of Amiens
Amiens Cathedral
The Cathedral of Our Lady of Amiens , or simply Amiens Cathedral, is a Roman Catholic cathedral and seat of the Bishop of Amiens...

, Le Mans and Beauvais.

Later Gothic buildings continued to use flying buttresses but often embellished them with crockets on the flyers and figural sculpture in niches or aedicules set into the buttresses. Renaissance and later architecture eschewed the flying buttress in favour of thick-wall construction. However the design was revived by Canadian architect William P. Anderson
William P. Anderson
Colonel William Patrick Anderson was a Canadian civil engineer. He was Superintendent of Lighthouses for almost 40 years, and was responsible for many of the more notable lighthouses in Canada.-Early life and career:...

 to build lighthouse
Lighthouse
A lighthouse is a tower, building, or other type of structure designed to emit light from a system of lamps and lenses or, in older times, from a fire, and used as an aid to navigation for maritime pilots at sea or on inland waterways....

s at the beginning of the 20th century.

Construction

Because the majority of the load is transmitted from the ceiling through the upper part of the walls, making the buttress as a semi-arch extending far from the wall provides almost the same load-bearing capacity as a traditional buttress engaged with the wall from top to bottom, yet in a much lighter and cheaper structure. And because the flying buttress relieves the load-bearing walls with a much smaller area of contact, much larger voids are able to be built into those walls, such as for windows, than would otherwise be possible.

Often on Gothic churches, two arched 'flyers' were used one above the other. In such cases the lower flyer (positioned a little below the springing point of the vault) is designed to take the lateral force of the vault while the upper one resists the effect of wind-loading on the roof.

The vertical buttresses at the outer end of the flyers were often capped with pinnacle
Pinnacle
A pinnacle is an architectural ornament originally forming the cap or crown of a buttress or small turret, but afterwards used on parapets at the corners of towers and in many other situations. The pinnacle looks like a small spire...

s that provide additional vertical loading to help resist the lateral thrust transmitted by the flyer.

Remedial

Another application of the flying buttress is to prop up a wall which may be leaning with a danger of collapse. An example is found at Chaddesley Corbett
Chaddesley Corbett
Chaddesley Corbett is a village and civil parish in the Wyre Forest District of Worcestershire, England. The civil parish also includes the settlements of Bluntington, Brockencote, Mustow Green, Cakebole, Outwood, Harvington, and Drayton....

, where the wall of the south aisle of the parish church is leaning outwards. A flying buttress has been added as a more practical option instead of dismantling the wall and rebuilding it. The aisle was built in the 14th century, and dismantling it would be a major work. The accompanying picture also shows another form of buttress.

See also

  • Buttress
    Buttress
    A buttress is an architectural structure built against or projecting from a wall which serves to support or reinforce the wall...

  • Cathedral architecture
  • Gothic architecture
    Gothic architecture
    Gothic architecture is a style of architecture that flourished during the high and late medieval period. It evolved from Romanesque architecture and was succeeded by Renaissance architecture....

  • Seismic retrofit
    Seismic retrofit
    Seismic retrofitting is the modification of existing structures to make them more resistant to seismic activity, ground motion, or soil failure due to earthquakes. With better understanding of seismic demand on structures and with our recent experiences with large earthquakes near urban centers,...

The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
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